Submission #833193

#	Time	Username	Problem	Language	Result	Execution time	Memory
833193		vjudge1	Bomb (IZhO17_bomb)	C++17	22 / 100	1097 ms	73976 KiB

bomb

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
// using ld = long double;
#define all(x) begin(x), end(x)
#ifdef LOCAL
#define debug(...) __VA_ARGS__;
#else
#define debug(...)
#endif

template<class A, class B> ostream& operator<<(ostream& os, const pair<A, B> &p);
template<class T> ostream& operator<<(ostream& os, const vector<T> &v);
template<class T, size_t N> ostream& operator<<(ostream& os, const array<T, N> &v);

template<class A, class B>
ostream& operator<<(ostream& os, const pair<A, B> &p) {
  return os << '(' << p.first << ',' << p.second << ')';
}
 
template<class T>
ostream& operator<<(ostream& os, const vector<T> &v) {
  os << '{'; bool fs = 1;
  for(auto &i : v) { if(!fs) os << ','; os << i; fs = 0; }
  return os << '}';
}

template<class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N> &v) {
  os << '{'; bool fs = 1;
  for(auto &i : v) { if(!fs) os << ','; os << i; fs = 0; }
  return os << '}';
}

void init() {
}
 
void solve(int tt = 0) {
  int n, m; cin >> n >> m;
  vector a(n, vector<int>(m));
  bool ok = 0;
  for(auto &v : a) for(int &i : v) {
    char c; cin >> c;
    i = c - '0';
    ok |= i;
  }
  if(!ok) return void(cout << 0 << '\n');
  vector pref(n, vector<int>(m));
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < m; j++) {
      pref[i][j] = a[i][j];
      if(i) pref[i][j] += pref[i-1][j];
      if(j) pref[i][j] += pref[i][j-1];
      if(i > 0 && j > 0) pref[i][j] -= pref[i-1][j-1];
    }
  }
  const auto get = [&](int i1, int j1, int i2, int j2) -> int {
    int ans = pref[i2][j2];
    if(i1) ans -= pref[i1-1][j2];
    if(j1) ans -= pref[i2][j1-1];
    if(i1 && j1) ans += pref[i1-1][j1-1];
    return ans;
  };
  vector b(n, vector<int>(m));
  const int INF = 1e9;
  int ans = 0;
  for(int h = 1; h <= n; h++) {
    debug(cerr << "h = " << h << '\n');
    int best = INF;
    for(int i = 0; i+h-1 < n; i++) {
      int consec = 0;
      for(int j = 0; j < m; j++) {
        int x = (get(i, j, i+h-1, j) == h);
        debug(cerr << x);
        if(x) {
          consec++;
          for(int k = i; k < i+h; k++)
            b[k][j] = 1;
        } else {
          if(consec != 0) best = min(best, consec);
          consec = 0;
        }
      }
      if(consec != 0) best = min(best, consec);
      debug(cerr << '\n');
    }
    debug(cerr << "best = " << best << '\n');
    if(best != INF && a == b) ans = max(ans, best * h);
    for(int i = 0; i < n; i++) {
      for(int j = 0; j < m; j++)
        b[i][j] = 0;
    }
  }
  cout << ans << '\n';
}

void reset() {
}
 
int main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; // cin >> t;
  init();
  for(int i = 1; i <= t; i++) solve(i), reset();
  return 0;
}

• Subtask 1: 22 / 100